doodle/pkg/physics/vector.go

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package physics
import (
"fmt"
"math"
"git.kirsle.net/go/render"
)
// Vector holds floating point values on an X and Y coordinate.
type Vector struct {
X float64
Y float64
}
// NewVector creates a Vector from X and Y values.
func NewVector(x, y float64) Vector {
return Vector{
X: x,
Y: y,
}
}
// VectorFromPoint converts a render.Point into a vector.
func VectorFromPoint(p render.Point) Vector {
return Vector{
X: float64(p.X),
Y: float64(p.Y),
}
}
// IsZero returns if the vector is zero.
func (v Vector) IsZero() bool {
return v.X == 0 && v.Y == 0
}
// Add to the vector.
func (v *Vector) Add(other Vector) {
v.X += other.X
v.Y += other.Y
}
// ToPoint converts the vector into a render.Point with integer coordinates.
func (v Vector) ToPoint() render.Point {
return render.Point{
X: int(math.Round(v.X)),
Y: int(math.Round(v.Y)),
}
}
// String encoding of the vector.
func (v Vector) String() string {
return fmt.Sprintf("%f,%f", v.X, v.Y)
}